The network is under heavy congestion right now and there is around 55,000 unconfirmed transactions in the mempool. This means that it is requiring larger fees for transactions to confirm in a timely manner.
If you are using Electrum to send the transactions, I recommend enabling the Dynamic fees within Preferences so that it can choose accurate fees. You can move the slider all the way to the right to ensure that fees are high enough for quick confirmations.
You can try to accelerate your unconfirmed transaction at
https://www.viabtc.com/tools/txaccelerator/ and see if that helps speed up the process.
